1. Ice crystal properties in high-altitude tropical anvil cirrus Detrained ice R e importance: Cloud albedo Anvil cirrus persistence Redistribution of H 2 O Entrainment of aerosols into updrafts  increasing ice concentration with height Entrainment dry air at cloud top  sublimation of small crystals Outline: Past measurements of tropical anvil cirrus microphysical properties What do Guam ATTREX observations tell us? E. Jensen, P. Lawson, S. Woods, S. Lance, B. Gandrud

2. STEP ER-2 (Darwin, 1987) Knollenberg et al. (JGR, 1993): Extremely high ice concentrations (10–100 cm -3 ) Modified 2D optical-array probe to mimic FSSP (accuracy difficult to assess)

3. Geophysica campaigns APE THESEO (1999), Scout-O 3 (2005), TROCCINOX (2005), SCOUT- AMMA (2006) Ice concentrations in cold anvil cirrus up to 1 cm -3 (Krämer et al., 2009); higher concentrations in fresh MCS outflow (Frey et al., 2011) Mostly FSSP only (+CIP on AMMA): shattering artifacts in anvil cirrus likely, crystals larger than 25–50 μm not measured  Not very useful for anvil cirrus Hector sampling EMERALD-II (2003), TWP-ICE (2006) Grob 520T Egrett (up to ~14.5 km), CPI and FSSP (Connolly et al., 2005) Proteus (up to ~16 km), FSSP, CDP, CIP (McFarquhar et al., 2007)

4. TC4 DC-8 (EastPac, 2007) 2D-S with shattering artifacts removed No higher than 12–13 km (sub-TTL) Mature anvil ice concentrations ~0.1 cm -3 Up to 10 cm -3 in updraft cores at 12 km  depletion by dilution and sublimation Information lacking for TTL anvil cirrus!

5. 4–5 March Global Hawk flight (RF03)

23. Vertical profile through Faxai cirrus band on GH climbout from Guam

24. 4–5 March Global Hawk flight (RF03)

30. Cirrus band sampled just south of Faxai

31. 4–5 March Global Hawk flight (RF03)

35. March 4-5 climbout through cirrus Aggregates and rosettes near cloud base

36. March 4-5 climbout through cirrus Aggregates and rosettes near cloud base

37. March 4-5 climbout through cirrus

39. Rosettes and small crystals at intermediate altitudes

40. March 4-5 climbout through cirrus

46. Only small crystals near cloud top

47. March 4-5 climbout through cirrus

51. March 4-5 closest approach to Faxai

57. Mostly rosettes and budding rosettes

58. March 4-5 closest approach to Faxai

61. 9-10 March Global Hawk flight (RF05)

65. Fresh anvil cirrus sampled

66. March 9-10 anvil cirrus

68. Large compact crystals, budding rosettes, some aggregates

69. March 9-10 anvil cirrus

73. Numerous small crystals (D<100 μm)

74. 2DS ice number concentration comparison

77. ATTREX anvils (14–16 km) generally have larger ice concentrations than lower TC4 anvils (<12 km) [1] Differences between ATTREX cases likely attributable to location in cloud, cloud age, etc. [1] Differences between TC4 2DS and ATTREX 2DS (Hawkeye) cannot be ruled out

78. Summary and outlook Relatively high-altitude anvil cirrus sampled during ATTREX appears to have more numerous, smaller crystals than lower TC4 anvils. – Convective parameterization R e assumptions should be adjusted accordingly. No evidence for extremely high ice concentrations reported by Knollenberg. Information about TTL anvil cirrus ice concentrations and sizes remains limited. Predominance of bullet rosettes suggests that much of the TTL “anvil” cirrus nucleates and grows in situ (consistent with Connolly et al. [2005]).